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Abstract:

A drive and steering unit for driving and steering a load support
comprises, in one embodiment, a steering assembly including a steering
gear attached to a wheel housing and engaged with the steering power
system, the steering gear being rotatable about an axis in response to
actuation of the steering assembly, a drive assembly connected to the
steering gear, and a drive power system coupled to the drive assembly and
movable with the steering gear. In an alternate embodiment, the steering
assembly is connected to the wheel through a steering gear attached to a
slewing ring that supports the drive assembly and is rotatable with the
drive assembly.

Claims:

1. A drive and steering unit comprising: a) a wheel housing having a
first axis that is aligned with a drive shaft of a wheel housed therein,
and a second axis that is normal to the first axis along a center of the
wheel; b) a steering assembly for steering the wheel and having a
steering gear and a steering power system coupled to the steering gear
for controlling and driving the steering gear; c) the steering gear being
attached to the wheel housing, having a central axis aligned with the
second axis, and being rotatable with the wheel housing about the second
axis; and d) a drive assembly coupled to the wheel housing for driving
the wheel, and a drive power system coupled to the drive assembly and
movable with the wheel housing.

2. The drive and steering unit of claim 1, wherein the steering gear is a
steering pulley attached to the wheel housing.

3. The drive and steering unit of claim 2, wherein the steering power
system is spaced from the wheel housing and coupled to the steering
pulley by a steering belt.

4. The drive and steering unit of claim 3, wherein the steering power
system further comprises a steering motor pulley, the steering belt
coupling the steering pulley to the steering motor pulley.

5. The drive and steering unit of claim 1, wherein the drive assembly is
mounted to the wheel housing and rotatable therewith.

6. The drive and steering unit of claim 5, wherein the drive power system
is attached to the wheel housing and coupled to the drive shaft by a
driving belt.

7. The drive and steering unit of claim 6, wherein the drive power system
further comprises a drive motor pulley, the driving belt coupling the
drive motor pulley to the drive shaft.

8. The drive and steering unit of claim 7, further comprising a drive
shaft pulley secured to the drive shaft that is coupled to the driving
belt.

9. The drive and steering unit of claim 1, wherein the wheel housing is
capable of up to or greater than 360.degree. degrees of movement.

10. The drive and steering unit of claim 1, wherein the wheel housing is
fixed to a support that defines a support plane and wherein the wheel
housing is mounted above the support plane.

11. The drive and steering unit of claim 10, wherein the wheel housing is
rotatable relative to the support by a bearing connected between the
wheel housing and the support.

12. The drive and steering unit of claim 11, wherein the drive assembly
is connected to the bearing.

13. The drive and steering unit of claim 1, wherein the steering assembly
and the drive assembly are each adapted to operate independently or
simultaneously.

14. An automated guided vehicle (AGV) comprising: a) a load support; and
b) a plurality of drive and steering units for driving and steering the
load support; c) each drive and steering unit comprising a steering
assembly including a steering gear attached to a wheel housing and
engaged with the steering power system, the steering gear being rotatable
about an axis in response to actuation of the steering assembly, a drive
assembly connected to the steering gear, and a drive power system coupled
to the wheel housing and movable with the steering gear.

15. The automated guided vehicle (AGV) of claim 14, wherein the steering
gear is a steering pulley attached to the wheel housing.

16. The automated guided vehicle (AGV) of claim 15, wherein the steering
power system is spaced from the wheel housing and coupled to the steering
pulley by a steering belt.

17. The automated guided vehicle (AGV) of claim 16, wherein the steering
power system further comprises a steering motor pulley, the steering belt
coupling the steering pulley to the steering motor pulley.

18. The automated guided vehicle (AGV) of claim 14, wherein the drive
assembly is mounted to the wheel housing and rotatable therewith.

19. The automated guided vehicle (AGV) of claim 18, wherein the drive
power system is attached to the wheel housing and coupled thereto by a
driving belt.

20. The automated guided vehicle (AGV) of claim 14, wherein the wheel
housing is capable of up to or greater than 360.degree. degrees of
movement.

21. The automated guided vehicle (AGV) of claim 14, wherein the wheel
housing is fixed to a support that defines a support plane and wherein
the wheel housing is mounted above the support plane.

22. The automated guided vehicle (AGV) of claim 21, wherein the wheel
housing is rotatable relative to the support by a bearing connected
between the wheel housing and the support.

23. The automated guided vehicle (AGV) of claim 22, wherein the drive
assembly is connected to the bearing.

24. The automated guided vehicle (AGV) of claim 14, wherein the steering
assembly and the drive assembly are each adapted to operate independently
or simultaneously.

25. The automated guided vehicle (AGV) of claim 14, further comprising
four drive and steering units positioned along adjacent corners of the
load support, the steering assemblies being fixed adjacent a periphery of
the load support.

26. A drive and steering unit comprising: a) a steering assembly for
steering a wheel and having a steering gear and a steering power system
coupled to the steering gear for controlling and driving the steering
gear; b) a slewing ring attached to the steering gear for rotating the
wheel; and c) a drive assembly coupled to the slewing ring for driving
the wheel, and a drive power system coupled to the drive assembly and
movable with the slewing ring and the wheel.

27. The drive and steering unit of claim 26, wherein the steering power
system is spaced from the slewing ring by a steering belt.

28. The drive and steering unit of claim 27, wherein the steering power
system further comprises a steering motor pulley, the steering belt
coupling the steering pulley to the steering motor pulley.

29. The drive and steering unit of claim 26, wherein the drive assembly
is mounted to the slewing ring and rotatable therewith.

30. The drive and steering unit of claim 29, wherein the drive power
system is attached to the slewing ring and coupled to the wheel by a
driving belt.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit under 35 U.S.C. §119(e)
from U.S. Application 61/505,698, filed Jul. 8, 2011. This application is
also related to U.S. application Ser. No. 13/004,552 filed Jan. 11, 2011,
which claims the benefit of U.S. Application 61/294,932, filed Jan. 14,
2010. This application is also related to U.S. Application 61/145,543,
filed Jan. 17, 2009, and U.S. Application 61/248,448, filed Oct. 3, 2009,
and U.S. Application 61/258,006, filed Nov. 4, 2009. The contents of each
of the above applications are incorporated herein by reference in their
entirety.

FIELD OF THE INVENTION

[0002] The present invention relates to a wheel drive and steering unit
for, in one embodiment, a load support such as an automatic guided
vehicle (AGV) and other semi-automatic or manually controlled vehicles.

BACKGROUND

[0003] Conventional AGVs rely upon gear units that house separate drive
and steering components that are adjacent to a load carried by a vehicle.
For example, conventional AGVs employ two turnable and two non-turnable
wheels, much like a forklift, where the drive and steering mechanisms are
adjacent to the load. That design simplifies the mechanical components of
the system, but limits the amount of the load a vehicle can carry and the
maneuverability of the vehicle. The load is limited because the placement
of the drive and steering components adjacent to the load increases the
top-heaviness of the vehicle. Maneuverability is constrained because only
two wheels are capable of turning.

[0004] In addition, existing drive and steering units are relatively
delicate in construction, large in design, and provide minimal power for
steering, drive, and load bearing functions relative to the overall size
of the unit.

SUMMARY

[0005] A drive and steering unit, incorporated in one embodiment in an AGV
for example, is provided for driving and steering a load support, such as
a tray or a storage locker for example, and includes a steering assembly
for steering a wheel and a drive assembly for driving the wheel. In one
embodiment, the steering assembly includes a steering gear attached to a
wheel housing that houses the wheel, the steering gear being engaged with
the steering power system and being rotatable about an axis in response
to actuation of the steering assembly. The drive assembly is connected to
the steering gear and is coupled to a drive power system for driving the
wheel, the drive assembly being movable with the steering gear. In an
alternate embodiment, the steering assembly is connected to the wheel
through a steering gear attached to a slewing ring that supports the
drive assembly and is rotatable with the drive assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The accompanying drawings, which are incorporated in and form a
part of this specification, illustrate certain embodiments of an
omnidirectional drive and steering unit and together with the
description, serve to explain certain aspects of the principles of this
application.

[0007] FIG. 1 is a top view of one embodiment of an AGV including a
steering and drive unit of the present disclosure.

[0008] FIG. 2 is a perspective view of an AGV carrying a load.

[0009] FIG. 3 is a perspective view of one embodiment of a steering and
drive unit.

[0013]FIG. 7 illustrates a rotation profile of the steering and drive
unit.

[0014]FIG. 8 illustrates an alternate embodiment of a steering and drive
unit of the present disclosure.

[0015] FIG. 9 illustrates one view of one part of a steering assembly.

[0016] FIG. 10 is a cross section taken through the part of the steering
assembly of FIG. 9.

[0017] FIG. 11 illustrates one view of a portion of a drive assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] This disclosure describes the best mode or modes of practicing the
invention as presently contemplated. This description is not intended to
be understood in a limiting sense, but provides an example of the
invention presented solely for illustrative purposes by reference to the
accompanying drawings to advise one of ordinary skill in the art of the
advantages and construction of the invention. In the various views of the
drawings, like reference characters designate like or similar parts.

[0019] FIG. 1 is a top view of one embodiment of an AGV 100 including a
frame 110, a support surface or platform 120 that defines a support plane
and a plurality of drive and steering units 200 secured to the bottom 130
of the frame 110. The support platform 120 is partially cut away for
purposes of clarity to show the drive and steering units 200, it being
understood that the support platform 120 would preferably extend to the
borders of the frame 110 and would completely enclose the drive and
steering units 200 with only the drive wheel being visible from the
bottom or underside of the AGV 100. The support platform 120 comprises a
load support on which a load 150 (FIG. 2) is placed for transport by the
AGV 100. Such load could, for example, comprise a tray upon which a
vehicle or the like is driven and/or stored as described in U.S.
Application 61/258,006 ("the '006 application"). Alternatively, the load
could be a storage locker as also described in the '006 application.
Other non-limiting variations of loads are contemplated.

[0020] The embodiment of the AGV 100 shown in FIG. 1, for example, is
generally rectangular in construction with drive and steering units 200
positioned at each corner 140. However, the configuration of the AGV 100
need not be so limited. The AGV 100 could, for example, have a footprint
that is square, oval, circular or the like (not shown). The AGV 100 could
be any shape or configuration without departing from its lift and
transport requirements. In addition, while four drive and steering units
200 are shown, it will be understood that other than four drive and
steering units 200 may be utilized, at various locations relative to the
frame 110, if desired by the needs of the user and taking into account
the load demands and configurations. Such drive and steering units 200
may be operated simultaneously or independently of each other. However,
it will be appreciated that from a manufacturing and operational
perspective, the use of four identical drive and steering units, if
desired, is preferable in order to take advantage of efficiencies with
regards to controls, electrical, mechanical, wiring and other components.

[0021] FIGS. 3-7 illustrate one embodiment of a drive and steering unit
200 that is incorporated into an AGV 100 as shown, for example, in FIG.
1, for engaging a wheel housing 300 having a wheel 310 therein. The wheel
housing 300 is fixed to the bottom 130 of the frame 110, which forms a
support 130 for the wheel housing 300 and which defines a support plane.
Mounting the wheel housing 300 above the plane of the support 130
provides easier access to the drive and steering units 200 for purposes
of service and maintenance. The wheel housing 300 is rotatable relative
to the support 130 by a bearing 160 enclosed within a bearing housing 170
that is connected between the wheel housing 300 and the support 130. The
wheel housing 300 has a first axis 302 that is aligned with a drive shaft
330 of the wheel 310 housed therein, and a second axis 304 that is normal
to the first axis 302 along a center of the wheel 310.

[0022] The drive and steering unit 200 further comprises a steering
assembly 400 for steering the wheel 310 and a drive assembly 500 for
driving the wheel 310, each of the steering assembly 400 and the drive
assembly 500 being capable of operating simultaneously or independent of
each other. The steering assembly 400 includes a steering gear 410 and a
steering power system 420 coupled to the steering gear 410 for
controlling and driving the steering gear 410. The steering power system
420 further comprises a steering motor 430 that drives a steering motor
pulley 440 through a gearbox 450. The steering gear 410 is attached to
the wheel housing 300 and has a central axis aligned with the second axis
304 of the wheel housing 300, such that the wheel housing 300 is
rotatable with the steering gear 410 about the second axis 304 and is
thus steered by the movement of the steering gear 410. More specifically,
the steering motor 430 drives the steering motor pulley 440 that in turn
drives the steering gear 410 through the coupling of the steering gear
410 and the steering motor pulley 440 by a steering belt 415. The
steering power system 420 is spaced from the wheel housing 300 and is
coupled thereto by the steering belt 415, which belt 415 is maintained in
proper engagement by a tensioner 417 attached to the gearbox 450. While a
belt 415 is described, it will be appreciated that other implements may
be used such as a chain, for example.

[0023] The drive assembly 500 is coupled to the wheel housing 300 for
driving the drive shaft 330 of the wheel 310. The drive assembly 500
includes a driving pulley 510 and a drive power system 520 coupled to the
driving pulley 510 by a connector plate 512 for controlling and driving
the drive shaft 330 of the wheel 310 through the driving pulley 510. The
drive power system 520 further comprises a driving motor 530 that drives
a driving motor pulley 540 coming directly off the driving motor 530. The
driving pulley 510 is attached to the drive shaft 330 and is coaxial
therewith, such that the drive shaft 330 is rotatable with the driving
pulley 510 and is thus driven thereby. More specifically, the driving
motor 530 drives the driving motor pulley 540 that in turn drives the
driving pulley 510 through the coupling of the driving pulley 510 and the
driving motor pulley 540 by a driving belt 515, which belt 515 is
maintained in proper engagement by a tensioner 517 attached to the
connector plate 512. While a belt 515 is described, it will be
appreciated that other implements may be used such as a chain, for
example.

[0024] In the illustrated embodiment, the drive power system 520 is not
spaced from the wheel housing 300 but is instead attached or mounted
thereto by the connector plate 512 and an additional connection 514. The
drive power system 520 is thus rotatable with the wheel housing 300
preferably along a 360° degree profile 600 through which the drive
power system 520 travels, which provides a turning range for steering and
control of up to or greater than 360° degrees, such as 370°
degrees for example, thereby allowing greater and more efficient steering
control and the ability to perform more complex tasks. The steering power
system 420 is thus spaced from the wheel housing 300 a sufficient
distance to accommodate the travel profile of the drive power system 520.

[0025] Thus, there is described, in one embodiment, an AGV 100 comprising
a load support 120, a plurality of drive and steering units 200 for
driving and steering the load support 120, each drive and steering unit
200 comprising a steering assembly 400 including a steering gear 410
attached to a wheel housing 300 and engaged with the steering power
system 420, the steering gear 410 being rotatable about an axis 304 in
response to actuation of the steering assembly 400, a drive assembly 500
connected to the steering gear 410, and a drive power system 520 coupled
to the wheel housing 300 and movable with the steering gear. The drive
and steering units 200 are each independently capable of up to or greater
than 360° degree movement, which results in a highly controllable,
agile and responsive movement and enables a user to easily maneuver a
load 150 around obstacles (not shown) and locate the AGV 100 within tight
storage locations (not shown). Furthermore, the wheel housing 300 is
mounted above the support plane, which enables easier access to the drive
and steering units 200 for purposes of service and maintenance.

[0026] FIGS. 8 through 11 illustrate an alternate embodiment of a drive
and steering unit 700 that is incorporated into an AGV as shown, for
example, in FIG. 1, for engaging a wheel 710, and that is similar in
certain respects to the drive and steering unit disclosed in the '066
application incorporated herein by reference. The drive and steering unit
700 further comprises a steering assembly 800 for steering the wheel 710
and a drive assembly 900 for driving the wheel 710, each of the steering
assembly 800 and the drive assembly 900 being capable of operating
simultaneously or independent of each other. The steering assembly 800
includes a steering gear 810 and a steering power system 820 coupled to
the steering gear 810 for controlling and driving the steering gear 810.
The steering power system 820 further comprises a steering motor 830 that
drives a steering motor pulley 840 through a gearbox 850. The steering
gear 810 is attached to a slewing ring 805 that supports both a drive
shaft 730 of the wheel 710 and the drive assembly 900, the slewing ring
805 being rotatable with the steering gear 810 and being steered by the
movement of the steering gear 810. More specifically, the steering motor
830 drives the steering motor pulley 840 that in turn drives the steering
gear 810 through the coupling of the steering gear 810 and the steering
motor pulley 840 by a steering belt 815. The steering power system 820 is
spaced from the wheel 710, steering gear 810 and slewing ring 805 and is
coupled thereto by the steering belt 815, which belt 815 is maintained in
proper engagement by a tensioner 817 attached to the gearbox 850. While a
belt 815 is described, it will be appreciated that other implements may
be used such as a chain, for example.

[0027] The drive assembly 900 is coupled to the wheel 710 and slewing ring
805 for driving the drive shaft 730 of the wheel 710. The drive assembly
900 includes a driving pulley 910 and a drive power system 920 coupled to
the driving pulley 910 for controlling and driving the drive shaft 730
(FIG. 10) of the wheel 710 through the driving pulley 910. The drive
power system 920 further comprises a driving motor 930 that drives a
driving motor pulley 940 coming directly off the driving motor 930. The
driving pulley 910 is attached to the drive shaft 730 and is coaxial
therewith, such that the drive shaft 730 is rotatable with the driving
pulley 910 and is thus driven thereby. More specifically, the driving
motor 930 drives the driving motor pulley 940 that in turn drives the
driving pulley 910 through the coupling of the driving pulley 910 and the
driving motor pulley 940 by a driving belt 915, which belt 915 is
maintained in proper engagement by a tensioner 917 (FIG. 11). While a
belt 915 is described, it will be appreciated that other implements may
be used such as a chain, for example.

[0028] In the illustrated embodiment, the drive power system 920 is
attached or mounted to the slewing ring 805, which is attached to the
steering gear 810. Thus, the drive power system 920 is rotatable with the
steering gear 810 and slewing ring 805 along a profile that is less than
360° degrees, including, but not limited to, 210° degrees,
for example. Other travel profile dimensions are possible. Movement of
the slewing ring 805 is also limited by a cable 807 spanning the slewing
ring 805 and the support 705 and a hard stop block 808 (FIG. 10) attached
to the slewing ring 805. Thus, the slewing ring 805 supports both the
drive assembly 900 and the drive power system 920 and is able to
dynamically and robustly steer or rotate the drive wheel 710 and carry
the drive power system 920 under an appreciable load. The robust
load-bearing contribution of the slewing ring 805 allows the use of an
increased diameter drive wheel 710, if desired, with a preferred wheel
diameter of approximately eight inches, for example. Other dimensions are
possible.

[0029] During operation of the steering and drive unit 700, forward and
backward movement is controlled by the drive power system 920 acting on
the driving pulley 910 through the driving belt 915. Rotation of the
wheel 710, for steering an AGV for example, is executed by rotating the
steering gear 810, which in turn rotates the slewing ring 805 that acts
on the drive shaft 730. As noted above, the forward/backward motion and
steering motion can be affected independently or simultaneously.

[0030] While the present invention has been described at some length and
with some particularity with respect to the several described
embodiments, it is not intended that it should be limited to any such
particulars or embodiments or any particular embodiment, but it is to be
construed with references to the appended claims so as to provide the
broadest possible interpretation of such claims in view of the prior art
and, therefore, to effectively encompass the intended scope of the
invention. Furthermore, the foregoing describes the invention in terms of
embodiments foreseen by the inventor for which an enabling description
was available, notwithstanding that insubstantial modifications of the
invention, not presently foreseen, may nonetheless represent equivalents
thereto.